A MIMO communication system employs multiple transmit antennas and receive antennas for transmission and reception. Generally, a capacity and performance are improved as the number of transmit and receive antenna increases. With multiple antennas, multiple channels are established between the transmitter and the receiver.
Generally, a transmitter is in restriction on transmit power and therefore should implement transmit power control. The transmitter allocates transmit power within the allowable maximum transmit power limit. Each channel of the MIMO system experiences different channel conditions. For example, multipath and fading conditions may vary on each channel.
Some systems use single carrier with frequency domain equalization (SC-FDE) at a receiver which uses no feedback. Therefore, these systems suffer from poor system throughput and capacity. Other systems use slow feedback systems.